Acquisitions and Dispositions - Narrative (Details) shares in Thousands, $ in Thousands, € in Millions, £ in Millions										3 Months Ended			9 Months Ended
	Jul. 03, 2023 USD ($)	Apr. 25, 2023 USD ($)	Apr. 25, 2023 EUR (€)	Oct. 03, 2022 USD ($)	Jul. 15, 2022 USD ($)	Jul. 12, 2022 USD ($)	May 31, 2022 USD ($)	Apr. 19, 2022 USD ($)	Apr. 01, 2022 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($) shares	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Oct. 03, 2022 GBP (£)	Jul. 12, 2022 GBP (£)
Business Acquisition [Line Items]
Goodwill										$ 1,572,489	$ 1,566,956		$ 1,572,489
Revenues										617,573		$ 663,791	1,872,282	$ 1,979,607
Income attributable to noncontrolling interests										2,464		24,665	(8,548)	59,668
Net Income (Loss) Attributable to Parent										653		10,609	(3,597)	33,747
Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest										3,117		35,274	(12,145)	93,415
Hello Design
Business Acquisition [Line Items]
Aggregate purchase price									$ 4,600
Closing cash payment									3,600
Deferred acquisition consideration									$ 1,000
BNG
Business Acquisition [Line Items]
Aggregate purchase price								$ 20,900
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life								10 years
Goodwill								$ 24,643
Estimated contingent consideration								$ 50,000
Contingent consideration payable in cash (percent)								67.00%
Contingent consideration payable in equity (percent)								33.00%
Revenues										7,700		5,900	21,800	11,200
Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest										(700)		(2,500)	(200)	(2,600)
BNG | Customer Relationships
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life								10 years
TMA Direct
Business Acquisition [Line Items]
Remaining ownership interest acquired (percent)							87.00%
Aggregate purchase price							$ 17,200
Deferred acquisition consideration							$ 500
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life							10 years
Goodwill							$ 6,569
Business Acquisition, Percentage of Voting Interests Acquired, Step One							13.00%
Business Combination, Contingent Consideration Arrangements, Change in Range of Outcomes, Contingent Consideration, Liability, Value, High							$ 13,300
Revenues										2,100		3,800	8,700	5,000
Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest										300		$ 1,400	700	$ 1,600
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles							$ 13,200,000	$ 12,740
Business Acquisition, Percentage of Voting Interests Acquired, Step One							13.00%
Business Combination, Contingent Consideration Arrangements, Change in Range of Outcomes, Contingent Consideration, Liability, Value, High							$ 13,300
TMA Direct | Customer Relationships
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life							10 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles							$ 1,800,000	$ 6,150
Epicenter
Business Acquisition [Line Items]
Closing cash payment				$ 9,900
Deferred acquisition consideration				$ 5,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				5 years
Goodwill				$ 4,416
Revenues										1,100			3,300
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net				$ 11,864
Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest										(100)			100
PEP Group
Business Acquisition [Line Items]
Aggregate purchase price						$ 500
Estimated contingent consideration | £																£ 2.6
Apollo
Business Acquisition [Line Items]
Aggregate purchase price					$ 2,300
Payments to Acquire Business, First Payment					1,000
Payments to Acquire Business, Second Payment					$ 1,500
Maru Group
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				8 years
Goodwill				$ 26,033
Revenues										7,700			25,500
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net				25,794											£ 23.0
Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest										(3,200)			(7,600)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles				$ 14,300
Maru Group | Customer Relationships
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				10 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles				$ 4,900
Wolfgang
Business Acquisition [Line Items]
Remaining ownership interest acquired (percent)				80.00%											80.00%
Closing cash payment				$ 3,800
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				5 years
Goodwill				$ 2,451
Revenues										1,500			3,600
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net				6,160
Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest										$ 100			$ 400
Wolfgang | Common Class A
Business Acquisition [Line Items]
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable				$ 1,200
Shares issued by the Company (shares) | shares											175
Huskies [Member]
Business Acquisition [Line Items]
Aggregate purchase price		$ 5,600	€ 5.2
Goodwill		2,600
Business Combination, Payables to Sellers		$ 1,000	€ 0.9
Tinsel
Business Acquisition [Line Items]
Aggregate purchase price	$ 2,500
Goodwill	$ 1,600